Re: [PATCH V5 1/6] Sched: Scheduler time slice extension

[Prakash Sangappa]

> On Jun 9, 2025, at 2:52 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> 
> On Mon, 9 Jun 2025 16:55:32 -0400
> Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> 
>> So I applied your patches and fixed up my "extend-sched.c" program to use
>> your method. I booted on bare-metal PREEMPT_RT and ran:
> 
> In case anyone else wants to play, I'm attaching the source of extend-sched.c
> 
> I ran it with: sleep 5; ./extend-sched
> 
> Then switched over to cyclic test, counted to five and it was pretty
> noticeable when it triggered.
> 
> To build, simply do:
> 
>  $ cd linux.git
>  $ mkdir /tmp/extend
>  $ cp tools/testing/selftests/rseq/rseq-abi.h /tmp/extend
>  $ cd /tmp/extend
> 
>  [ download extend-sched.c here ]
> 
>  $ gcc extend-sched.c -o extend-sched
> 
> 
> -- Steve
> <extend-sched.c>

Thanks for sharing the test program.

In test program, unextend() should be slightly modified as follows.

101c101
< 	if (!(flags & (1 << 4)))
---
> 	if (flags & (1 << 3))
103,106c103,107
< 
< 	tracefs_printf(NULL, "Yield!\n");
< 	sched_yield();
< 		return 1;
---
> 	if (!(flags & (1 << 4))) {
> 		tracefs_printf(NULL, "Yield!\n");
> 		sched_yield();
> 	}
> 	return 1;